Cast components having surfaces with resin coatings

ABSTRACT

Lightweight and strong components may be manufactured using foam material compositions and resin coating materials by the processes described herein. One or more mandrels and/or a molding tool may be coated with resin coatings, the one or more mandrels may be inserted into the molding tool, and a foam material composition may be injected into the molding tool. After closing the molding tool, the foam material composition may expand and cure to form a component, and heat may be applied to cure the resin coatings into skins. For example, an external skin may be formed by the resin coatings on an exterior surface of the component in contact with surfaces of the molding tool, and one or more internal skins may be formed by the resin coatings on one or more interior surfaces of negative space spars of the component in contact with surfaces of the one or more mandrels.

BACKGROUND

Various components may be cast or molded using foam materialcompositions that expand and cure within molding tools. Such cast ormolded components may be lightweight, but may generally lack structuralstrength and be easily damaged during manufacturing, handling, and use.Accordingly, there is a need for systems and methods to create cast ormolded components having increased strength while also maintaining theirlightweight characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different figures indicates similaror identical components or features.

FIG. 1A is a schematic, perspective view diagram of a cast or moldedcomponent, according to an implementation.

FIG. 1B is a schematic, cross-sectional view diagram of a cast or moldedcomponent taken along line A-A′ shown in FIG. 1A, according to animplementation.

FIG. 1C is a schematic, partial cross-sectional view diagram of a castor molded component taken along line B-B′ shown in FIG. 1B, according toan implementation.

FIG. 1D is another schematic, cross-sectional view diagram of a cast ormolded component taken along line A-A′ shown in FIG. 1A, according to animplementation.

FIG. 1E is yet another schematic, cross-sectional view diagram of a castor molded component taken along line A-A′ shown in FIG. 1A, according toan implementation.

FIG. 2 is a flow diagram illustrating an example component with negativespace spar(s) formation process, according to an implementation.

FIG. 3A is a schematic, perspective view diagram of a cast or moldedcomponent, according to an implementation.

FIG. 3B is a schematic, cross-sectional view diagram of a cast or moldedcomponent taken along line A-A′ shown in FIG. 3A, according to animplementation.

FIG. 4 is a flow diagram illustrating an example component with negativespace spar(s) and resin coating formation process, according to animplementation.

FIG. 5A is a schematic, perspective view diagram of a thermallyexpanding mandrel, according to an implementation.

FIG. 5B is a schematic, perspective view diagram of another thermallyexpanding mandrel, according to an implementation.

FIG. 5C is a schematic, cross-sectional view diagram of a thermallyexpanding mandrel within a molding tool at a first temperature,according to an implementation.

FIG. 5D is a schematic, cross-sectional view diagram of a thermallyexpanding mandrel within a molding tool at a second temperature,according to an implementation.

FIG. 6 is a flow diagram illustrating an example component formationprocess using a thermally expanding mandrel, according to animplementation.

While implementations are described herein by way of example, thoseskilled in the art will recognize that the implementations are notlimited to the examples or drawings described. It should be understoodthat the drawings and detailed description thereto are not intended tolimit implementations to the particular form disclosed but, on thecontrary, the intention is to cover all modifications, equivalents andalternatives falling within the spirit and scope as defined by theappended claims. The headings used herein are for organizationalpurposes only and are not meant to be used to limit the scope of thedescription or the claims. As used throughout this application, the word“may” is used in a permissive sense (i.e., meaning having the potentialto), rather than the mandatory sense (i.e., meaning must). Similarly,the words “include,” “including,” and “includes” mean including, but notlimited to.

DETAILED DESCRIPTION

Systems and methods to form cast or molded components usingself-skinning foam materials having one or more negative space spars aredescribed. In addition, systems and methods to form cast or moldedcomponents having one or more surfaces with resin coatings are alsodescribed. Further, systems and methods to form cast or moldedcomponents having any desired shapes or forms using thermally expandingmandrels are described.

In example embodiments, various cast or molded components, such aswings, beams, or other components for aerial vehicles, may be formedusing self-skinning foam materials by the systems and methods describedherein. For example, a wing may be formed using a self-skinning foammaterial composition that is injected into a molding tool. In addition,the wing may include one or more negative space spars that are formedusing one or more mandrels inserted into the molding tool. Duringexpansion and curing of the self-skinning foam material composition, anexternal skin may be formed on an exterior surface of the wing, and/orone or more internal skins may be formed on interior surfaces of the oneor more negative space spars. The one or more negative space spars mayreduce material usage and weight of the wing, while the external skinand/or internal skins may increase structural strength of the wing.

In other example embodiments, various cast or molded components, such aswings, beams, or other components for aerial vehicles, may be formedhaving one or more surfaces with resin coatings by the systems andmethods described herein. For example, a wing may be formed using a foammaterial composition that is injected into a molding tool. In addition,the wing may include one or more negative space spars that are formedusing one or more mandrels inserted into the molding tool. Further, themolding tool and/or the one or more mandrels may include resin coatingsthat are applied on their respective surfaces. During expansion andcuring of the foam material composition, the resin coatings may also becured, e.g., by application of heat, such that an external skin may beformed from a resin coating on an exterior surface of the wing, and/orone or more internal skins may be formed from resin coatings on interiorsurfaces of the one or more negative space spars. The one or morenegative space spars may reduce material usage and weight of the wing,while the external skin and/or internal skins may increase structuralstrength of the wing.

In additional example embodiments, the external skin formed on anexterior surface of a component and/or the internal skins formed oninterior surfaces of the one or more negative space spars of a componentmay also include various surface features, such as corrugations, ribs,striations, protrusions, bumps, indentations, dimples, or other surfacefeatures, or combinations thereof. The various surface features may beformed from corresponding surface features on the molding tool and/orthe one or more mandrels, and such surface features may further increasethe structural strength of cast or molded components.

In further example embodiments, various cast or molded components, suchas wings, beams, or other components for aerial vehicles, may be formedusing thermally expanding mandrels by the systems and methods describedherein. For example, a thermally expanding mandrel may be formed from athermally expanding material composition, such as micronized rubberparticles and gypsum plaster. The thermally expanding mandrel may beformed in any desired shape or form. Then, component material, such ascarbon fiber strips or tape, may be applied to the thermally expandingmandrel and inserted into a molding tool. Upon the application of heatto the thermally expanding mandrel and/or the molding tool, the mandrelmay expand and apply pressure to the component material, and thecomponent material may be cured to form the component. Upon completionof expansion and curing of the component, the component may be removedfrom the molding tool, and the thermally expanding material compositionof the thermally expanding mandrel may be washed out of the component,e.g., using water, and at least partially reused or recycled in thesystems and methods described herein. The thermally expanding mandrelmay allow the formation of components having any desired shape or formwithin molding tools, while also facilitating reuse and/or recycling ofthe thermally expanding material composition.

FIG. 1A is a schematic, perspective view diagram of a cast or moldedcomponent 102, according to an implementation 100.

In example embodiments, the cast or molded component 102 may be a wing,beam, or other component of an aerial vehicle. In other exampleembodiments, the cast or molded component 102 may be any othercomponent, e.g., a beam, spar, rod, tube, or other component, of anyother type of vehicle, machine, structure, device, or system. AlthoughFIGS. 1A-1E depict an example wing as the cast or molded component 102,the systems and methods described herein are not limited to wings orother components of aerial vehicles.

The cast or molded component 102 may be formed from a foam materialcomposition, e.g., urethane or polyurethane foams. In exampleembodiments, the foam material composition may be an expanding foammaterial that expands and cures substantially at room temperature. Forexample, the foam material composition may expand and cure without theapplication of heat to the foam material composition. In alternativeembodiments, the foam material composition may be an expanding foammaterial that expands and cures upon application of heat. For example,the foam material composition may expand and cure at a faster rate uponapplication of heat as compared to the rate of expansion and curingsubstantially at room temperature.

In further example embodiments, the foam material composition may be aself-skinning foam material composition. For example, upon expansion ofthe foam material composition that results in a pressure increase atinterfaces between the foam material composition and one or moresurfaces of a molding tool and/or between the foam material compositionand one or more surfaces of one or more mandrels inserted into themolding tool, an external skin may be formed on an exterior surface ofthe component 102 and/or one or more internal skins may be formed on oneor more interior surfaces of the component 102.

Example foam material compositions may include four-pound self-skinningfoams, two-pound self-skinning foams, or other types of self-skinningfoams. For example, a four-pound foam indicates an expansion ratio ofapproximately four pounds per cubic foot, a two-pound foam indicates anexpansion ratio of approximately two pounds per cubic foot, etc. In someexample embodiments, self-skinning foams may form skins on theirexterior surface facing a molding tool, or interior surfaces facingmandrels, upon generation of at least approximately 10% overvolumepressure within a molding tool. In alternative embodiments, differentpercentages of overvolume pressure may be generated within the moldingtool, e.g., approximately 5%, approximately 8%, approximately 12%, orapproximately 15%, or within a range of approximately 5% toapproximately 20% overvolume pressure.

In some example embodiments, the foam material composition may bemodified with the addition of water or other additives to affect theexpansion ratio. For example, the addition of approximately five dropsof water to approximately 160 grams of two-pound self-skinning foam mayincrease the expansion ratio by approximately 30%.

As shown in FIG. 1A, the cast or molded component 102 may also includeone or more negative space spars 105. The negative space spars 105 maybe formed by the insertion of one or more mandrels into a molding toolthat forms the cast or molded component 102. Each of the negative spacespars 105 may have any desired shape based at least in part on a shapeof a corresponding mandrel. Although FIG. 1A shows three negative spacespars 105 within the cast or molded component 102, any other number orarrangement of negative space spars 105 may be included in the component102. For example, the component 102 may include only a single negativespace spar 105 in any position, or the component 102 may includemultiple negative space spars in any arrangement.

In example embodiments, the negative space spars 105 may reduce materialusage and weight of the component 102. Further, by forming the component102 using a self-skinning foam material composition, one or more skinsmay be formed on an exterior surface and/or one or more interiorsurfaces, and the one or more skins may increase structural strength ofthe component 102. For example, interlaminar shear strength between theone or more skins and other portions of the foam material compositionmay contribute to the increased structural strength of the component102.

FIG. 1B is a schematic, cross-sectional view diagram of a cast or moldedcomponent 102 taken along line A-A′ shown in FIG. 1A, according to animplementation.

FIG. 1B shows a component 102 formed of a foam material composition 103,e.g., a self-skinning foam material composition. An external skin 104may be formed on an exterior surface of the component 102 upon expansionand curing of the foam material composition that results in a pressureincrease at an interface between the foam material composition andsurfaces of a molding tool.

In addition, as shown in FIG. 1B, the component 102 may include threenegative space spars 105 a, 105 b, 105 c formed by the insertion ofcorresponding mandrels into the molding tool. Three internal skins 106a, 106 b, 106 c may be formed on interior surfaces of the three negativespace spars 105 a, 105 b, 105 c of the component 102 upon expansion andcuring of the foam material composition that results in a pressureincrease at interfaces between the foam material composition andsurfaces of corresponding mandrels.

In example embodiments, the negative space spars 105 a, 105 b, 105 c mayreduce material usage and weight of the component 102. Further, byforming the component 102 using a self-skinning foam materialcomposition, an external skin 104 may be formed on an exterior surfaceand one or more internal skins 106 a, 106 b, 106 c may be formed on oneor more interior surfaces, and the one or more skins 104, 106 a, 106 b,106 c may increase structural strength of the component 102. Forexample, interlaminar shear strength between the one or more skins andother portions of the foam material composition may contribute to theincreased structural strength of the component 102.

FIG. 1C is a schematic, partial cross-sectional view diagram of a castor molded component 102 taken along line B-B′ shown in FIG. 1B,according to an implementation.

As shown in FIG. 1C, the component 102 may also be formed with one ormore surface features 108 formed on one or more internal skins 106 ofthe component 102. The surface features 108 may be formed bycorresponding surface features included in surfaces of correspondingmandrels. The various surface features 108 may include corrugations,ribs, striations, protrusions, bumps, indentations, dimples, or othersurface features, or combinations thereof.

FIG. 1C shows three ribs 108 a, 108 b, 108 c formed on the internal skin106 b of the negative space spar 105 b. The three ribs 108 a, 108 b, 108c are shown as indentations that extend a greater depth into the foammaterial composition 103 than a remainder of the internal skin 106 b. Inother example embodiments, the ribs 108 may be formed as protrusionsthat extend a lesser depth into the foam material composition 103 than aremainder of the internal skin 106 b. In still other exampleembodiments, the internal skin 106 b may include any other type, number,or arrangement of surface features. Although FIG. 1C shows surfacefeatures only on internal skin 106 b within negative space spar 105 b,surface features of any type, number, or arrangement may also be formedon internal skins 106 of any other negative space spars 105.

FIG. 1D is another schematic, cross-sectional view diagram of a cast ormolded component 102 taken along line A-A′ shown in FIG. 1A, accordingto an implementation.

As shown in FIG. 1D, the component 102 may also be formed with one ormore other surface features 110 formed on one or more internal skins 106of the component 102. The surface features 110 may be formed bycorresponding surface features included in surfaces of correspondingmandrels. The various surface features 110 may include corrugations,ribs, striations, protrusions, bumps, indentations, dimples, or othersurface features, or combinations thereof.

FIG. 1D shows three sets of corrugations 110 a, 110 b, 110 c formed onthe internal skins 106 a, 106 b, 106 c of the negative space spars 105a, 105 b, 105 c. The three sets of corrugations 110 a, 110 b, 110 c areshown as peaks and valleys, or ridges and grooves, that extend along along axis of the component 102, e.g., along a length of a wing. In otherexample embodiments, the internal skins 106 a, 106 b, 106 c may includeany other type, number, or arrangement of surface features. AlthoughFIG. 1D shows the same or similar surface features on internal skins 106a, 106 b, 106 c within negative space spars 105 a, 105 b, 105 c,different or dissimilar surface features of any type, number, orarrangement may also be formed on internal skins 106 of the negativespace spars 105.

The various surface features may be formed by corresponding surfacefeatures included in surfaces of corresponding mandrels. In some exampleembodiments, the mandrels may be inflatable, adjustable, or expandingmandrels, or may include inflatable, adjustable, or expanding portionstherein, in order to form the surface features on the internal skins 106of the negative space spars 105. For example, inflatable mandrels orinflatable portions of mandrels may expand in size upon injection offluid, e.g., gas or liquid, into the mandrel and may reduce in size uponremoval of the fluid. Adjustable mandrels or adjustable portions ofmandrels may include movable or actuatable portions to selectivelymodify a shape or surface of the mandrel. Expanding mandrels orexpanding portions of mandrels may expand or reduce in size upon achange in condition, e.g., change in temperature, such as the thermallyexpanding mandrels described herein.

Although FIGS. 1C and 1D show various surface features formed on one ormore internal skins 106 of the component 102, various surface featuresmay also be formed on an external skin 104 of the component 102 bycorresponding surface features included in surfaces of a molding tool.

The various surface features may be formed by corresponding surfacefeatures included in surfaces of corresponding molding tools. In someexample embodiments, the molding tools may be inflatable, adjustable, orexpanding molding tools, or may include inflatable, adjustable, orexpanding portions therein, in order to form the surface features on theexternal skins 104 of the components 102. For example, inflatablemolding tools or inflatable portions of molding tools may expand in sizeupon injection of fluid, e.g., gas or liquid, into the molding tools andmay reduce in size upon removal of the fluid. Adjustable molding toolsor adjustable portions of molding tools may include movable oractuatable portions to selectively modify a shape or surface of themolding tools. Expanding molding tools or expanding portions of moldingtools may expand or reduce in size upon a change in condition, e.g.,change in temperature.

In example embodiments, the various surface features included on theinternal skins 106 of the negative space spars 105 and/or the externalskin 104 of the component 102 may further increase surface area ofcontact between the one or more skins and other portions of the foammaterial composition, thereby increasing interlaminar shear strengthbetween the one or more skins and other portions of the foam materialcomposition to further contribute to the increased structural strengthof the component 102. Moreover, with the inclusion of surface featureson one or more skins of the component 102 that increase structuralstrength, wall thicknesses between two or more skins of the componentmay be further reduced, thereby further reducing material usage andweight of the component 102 while increasing structural strength.

FIG. 1E is yet another schematic, cross-sectional view diagram of a castor molded component 102 taken along line A-A′ shown in FIG. 1A,according to an implementation.

As shown in FIG. 1E, the component 102 may also be formed with one ormore support materials 112 included at least partially within orattached or adhered to the foam material composition 103. For example,the support materials 112 may include a beam, rod, spar, or otherstructural support. In example embodiments, the support materials 112may be inserted into a molding tool and be surrounded by and molded intothe foam material composition 103. In other example embodiments, thesupport materials 112 may be inserted into, attached to, or adhered to acast or molded component 102 after the foam material composition hasexpanded and cured to form the component 102. The support materials 112may be formed of various types of materials, such as metals, plastics,woods, ceramics, polymers, or any other materials, or combinationsthereof. In addition, the support materials 112 may have any desiredshape.

FIG. 1E shows two support materials 112 a, 112 b included within thefoam material composition 103. For example, the support material 112 amay have an I-beam shape, and the support material 112 b may have aZ-spar shape. In other example embodiments, the component 102 mayinclude any other type, shape, number, or arrangement of supportmaterials 112.

In example embodiments, the various support materials included at leastpartially within or attached or adhered to the foam material compositionmay further contribute to the increased structural strength of thecomponent 102. Moreover, with the inclusion of support materials as partof the component 102 that increase structural strength, wall thicknessesof one or more portions of the component may be further reduced, therebyfurther reducing material usage and weight of the component 102 whileincreasing structural strength.

While FIGS. 1A-1E describe various aspects of cast or molded components102 individually, the various features described with respect to FIGS.1A-1E may be combined in various combinations. For example, externalskins 104 of components 102 and/or internal skins 106 of negative spacespars 105 may include combinations of various surface features, such asboth ribs 108 and corrugations 110 as described with respect to FIGS. 1Cand 1D. In addition, a first portion of a component 102 may includeskins 104, 106 with various surface features, and a second portion of acomponent 102 may include support materials 112. Various othercombinations of the various features described with respect to FIGS.1A-1E may also be included in cast or molded components 102.

FIG. 2 is a flow diagram illustrating an example component with negativespace spar(s) formation process 200, according to an implementation.

The process 200 may begin by preparing a molding tool and/or one or moremandrels, as at 202. For example, one or more release agents may beapplied to the molding tool and/or the one or more mandrels such that acast or molded component may be removed from the molding tool and/or theone or more mandrels may be removed from the component upon completionof the process 200. Further, the molding tool and/or the one or moremandrels may be designed with various draft angles to facilitate removalof a cast or molded component from the molding tool and/or removal ofthe one or more mandrels from the component. Moreover, the molding tooland/or the one or more mandrels may include various surface features asdescribed herein, in order to create corresponding surface features onexterior and/or interior surfaces of the component, such ascorrugations, ribs, striations, protrusions, bumps, indentations,dimples, or other surface features, or combinations thereof.

The molding tool may be a single-part, two-part, or multi-part moldingtool, and the molding tool may be formed from various materials, such asaluminum, carbon, steel, Inconel, other metals, ceramics, polymers,composites, or combinations thereof. In addition, the one or moremandrels may be solid or rigid mandrels, or inflatable, adjustable, orexpanding mandrels, and the one or more mandrels may be formed fromvarious materials, such as aluminum, carbon, steel, Inconel, othermetals, ceramics, polymers, composites, plastics, silicone, rubber, orcombinations thereof.

The process 200 may continue by inserting the one or more mandrels intothe molding tool, as at 204. For example, the one or more mandrels maybe placed in position within or relative to the molding tool, in orderto form the component with desired negative space spars at particularpositions and/or with a particular arrangement.

The process 200 may then proceed by preparing the foam materialcomposition, as at 206. For example, the foam material composition maybe a self-skinning foam material composition, as described herein. Inaddition, the foam material composition may be a two-part or multi-partcomposition of different materials that may begin to expand and cureupon mixing of the different materials. In some embodiments, the foammaterial composition may expand and cure within seconds, e.g., 10-59seconds, or minutes, e.g., 1-30 minutes. In other embodiments, the foammaterial composition may expand and cure over a shorter or longerduration of time. In example embodiments, the foam material compositionmay be cooled, e.g., down to about 15 degrees Fahrenheit, in order toslow the expansion and curing of the foam material composition andthereby increase the duration of time during which the foam materialcomposition may be prepared and handled. Further, the foam materialcomposition may be modified with the addition of water or otheradditives to affect the expansion ratio.

The process 200 may then continue by injecting the foam materialcomposition into the molding tool, as at 208. In addition, the foammaterial composition may by injected around the one or more mandrelsthat are inserted into or placed relative to the molding tool. Forexample, the foam material composition may be metered into the moldingtool such that a precisely measured or determined amount of foammaterial composition is injected into the molding tool. The amount offoam material composition to be injected or metered may be determinedbased at least in part on a volume of the cast or molded component and adesired overvolume pressure to be generated during expansion and curingof the foam material composition within the molding tool. As describedherein, in some example embodiments, self-skinning foams may form skinson their exterior surface facing the molding tool, and/or on theirinterior surfaces facing one or more mandrels, upon generation of atleast approximately 10% overvolume pressure within the molding tool. Inalternative embodiments, different percentages of overvolume pressuremay be generated within the molding tool, e.g., approximately 5%,approximately 8%, approximately 12%, or approximately 15%, or within arange of approximately 5% to approximately 20% overvolume pressure. Infurther example embodiments, prior to injecting the foam materialcomposition into the molding tool, one or more support materials asdescribed herein may be inserted or placed into the molding tool.

The process 200 may then proceed by closing the molding tool, as at 210.The closed molding tool may substantially seal the foam materialcomposition within the molding tool and/or around the one or moremandrels. In some example embodiments, prior to closing the moldingtool, one or more support materials as described herein may be insertedor placed into the molding tool. Then, the process 200 may continue byallowing the foam material composition to expand and cure, as at 212.Within the closed molding tool, the foam material composition maygenerate a desired overvolume pressure, such that one or more skins maybe formed on surfaces of the component.

After completion of the expansion and curing of the foam materialcomposition, the process 200 may continue by opening the molding tool,as at 214. Then, the process 200 may proceed by removing the componentfrom the molding tool, as at 216, and by removing the one or moremandrels from the component, as at 218. For example, the release agentsand/or draft angles of the molding tool may facilitate removal of thecomponent from the molding tool. Likewise, the release agents and/ordraft angles of the one or more mandrels may facilitate removal of theone or more mandrels from the component. In some example embodiments,after removing the component from the molding tool and/or after removingthe one or more mandrels from the component, one or more supportmaterials as described herein may be inserted, attached, or adhered tothe component. The process 200 may then end, as at 220.

The cast or molded component may include an external skin on an exteriorsurface of the component, and may also include one or more internalskins on interior surfaces of one or more negative space spars formed bythe one or more mandrels. As described herein, the one or more negativespace spars may reduce material usage and weight of the component, andinterlaminar shear strength between the one or more skins and otherportions of the foam material composition may contribute to theincreased structural strength of the component.

All or portions of the process 200 described herein may be performed byautomated or semi-automated machinery that is controlled and/orprogrammed to perform one or more steps of the process 200. For example,automated or semi-automated machinery or robotics may prepare themolding tool and/or the one or more mandrels for molding components,and/or may insert the one or more mandrels into the molding tool. Inaddition, automated or semi-automated machinery or robotics may preparethe foam material composition, and/or may inject or meter the foammaterial composition into the molding tool. Further, automated orsemi-automated machinery or robotics may close the molding tool to allowthe foam material composition to expand and cure, and/or may open themolding tool upon completion. Moreover, automated or semi-automatedmachinery or robotics may remove the component from the molding tool,and/or may remove the one or more mandrels from the component.

FIG. 3A is a schematic, perspective view diagram of a cast or moldedcomponent 302, according to an implementation 300.

In example embodiments, the cast or molded component 302 may be a wing,beam, or other component of an aerial vehicle. In other exampleembodiments, the cast or molded component 302 may be any othercomponent, e.g., a beam, spar, rod, tube, or other component, of anyother type of vehicle, machine, structure, device, or system. AlthoughFIGS. 3A and 3B depict an example wing as the cast or molded component302, the systems and methods described herein are not limited to wingsor other components of aerial vehicles.

The cast or molded component 302 may be formed from a foam materialcomposition, e.g., urethane or polyurethane foams, and one or more resincoatings, e.g., urethane resins, on surfaces of the component. Inexample embodiments, the foam material composition may be an expandingfoam material that expands and cures substantially at room temperature.For example, the foam material composition may expand and cure withoutthe application of heat to the foam material composition. In alternativeembodiments, the foam material composition may be an expanding foammaterial that expands and cures upon application of heat. For example,the foam material composition may expand and cure at a faster rate uponapplication of heat as compared to the rate of expansion and curingsubstantially at room temperature.

Example foam material compositions may include four-pound foams,two-pound foams, or other types of foams. For example, a four-pound foamindicates an expansion ratio of approximately four pounds per cubicfoot, a two-pound foam indicates an expansion ratio of approximately twopounds per cubic foot, etc. In some example embodiments, the foammaterial composition may be modified with the addition of water or otheradditives to affect the expansion ratio. For example, the addition ofapproximately five drops of water to approximately 160 grams oftwo-pound foam may increase the expansion ratio by approximately 30%.

The one or more resin coatings on surfaces of the component 302 may beformed from urethane resins. In some example embodiments, the urethaneresins may be modified with microspheres or other additives to reducethe weight of the urethane resins. For example, the microspheres may behollow glass, plastic, or polymer microspheres or microbeads. In furtherexample embodiments, the urethane resins may be modified with pigmentsor other coloring agents in order to form a component having a desiredcolor. In example embodiments, the resin coatings may cure substantiallyat room temperature. For example, the resin coatings may cure withoutthe application of heat to the resin coatings. In alternativeembodiments, the resin coatings may be cured with the application ofheat. For example, the resin coatings may cure at a faster rate uponapplication of heat as compared to the rate of curing substantially atroom temperature.

The one or more resin coatings may be applied to surfaces of a moldingtool and/or one or more mandrels, and the one or more resin coatings maybe cured, e.g., upon application of heat. For example, the molding tooland/or the one or more mandrels may be heated, e.g., placed in an oven,in order to cure the resin coatings. The curing of the resin coatingsmay at least partially overlap with the expansion and curing of the foammaterial composition. As a result, the resin coatings may form anexternal skin on an exterior surface of the component 302, and/or one ormore internal skins on interior surfaces of the component 302. Asdescribed herein, one or more negative space spars formed by the one ormore mandrels may reduce material usage and weight of the component 302,and interlaminar shear strength between the one or more skins formed byresin coatings and portions of the foam material composition maycontribute to the increased structural strength of the component 302.

As shown in FIG. 3A, the cast or molded component 302 may also includeone or more negative space spars 305. The negative space spars 305 maybe formed by the insertion of one or more mandrels into a molding toolthat forms the cast or molded component 302. Each of the negative spacespars 305 may have any desired shape based at least in part on a shapeof a corresponding mandrel. Although FIG. 3A shows three negative spacespars 305 within the cast or molded component 302, any other number orarrangement of negative space spars 305 may be included in the component302. For example, the component 302 may include only a single negativespace spar 305 in any position, or the component 302 may includemultiple negative space spars in any arrangement.

In example embodiments, the negative space spars 305 may reduce materialusage and weight of the component 302. Further, by forming the component302 using resin coatings around a foam material composition, one or moreskins may be formed by the resin coatings on an exterior surface and/orone or more interior surfaces, and the one or more skins may increasestructural strength of the component 302. For example, interlaminarshear strength between the one or more skins formed by the resincoatings and portions of the foam material composition may contribute tothe increased structural strength of the component 302.

FIG. 3B is a schematic, cross-sectional view diagram of a cast or moldedcomponent 302 taken along line A-A′ shown in FIG. 3A, according to animplementation.

FIG. 3B shows a component 302 formed of a foam material composition 303,e.g., an expanding foam material composition. An external skin 304 maybe formed on an exterior surface of the component 302 by a resin coatingapplied to surfaces of a molding tool and cured, e.g., by application ofheat, at least partially during expansion and curing of the foammaterial composition within the molding tool.

In addition, as shown in FIG. 3B, the component 302 may include threenegative space spars 305 a, 305 b, 305 c formed by the insertion ofcorresponding mandrels into the molding tool. Three internal skins 306a, 306 b, 306 c may be formed on interior surfaces of the three negativespace spars 305 a, 305 b, 305 c of the component 302 by resin coatingsapplied to surfaces of the corresponding mandrels and cured, e.g., byapplication of heat, at least partially during expansion and curing ofthe foam material composition within the molding tool.

In example embodiments, the negative space spars 305 a, 305 b, 305 c mayreduce material usage and weight of the component 302. Further, byforming the component 302 using an expanding foam material compositionand resin coatings on one or more surfaces, an external skin 304 may beformed on an exterior surface by a resin coating and one or moreinternal skins 306 a, 306 b, 306 c may be formed on one or more interiorsurfaces by resin coatings, and the one or more skins 304, 306 a, 306 b,306 c may increase structural strength of the component 302. Forexample, interlaminar shear strength between the one or more skinsformed by the resin coatings and portions of the foam materialcomposition may contribute to the increased structural strength of thecomponent 302.

As described herein with respect to FIGS. 1C-1E, the component 302 shownin FIGS. 3A and 3B may also be formed with one or more surface featuresformed on one or more internal skins 306 of the component 302. Thesurface features may be formed by corresponding surface featuresincluded in surfaces of corresponding mandrels. The various surfacefeatures may include corrugations, ribs, striations, protrusions, bumps,indentations, dimples, or other surface features, or combinationsthereof. In example embodiments, surface features of any type, number,or arrangement may be formed on internal skins 306 of any negative spacespars 305.

The various surface features may be formed by corresponding surfacefeatures included in surfaces of corresponding mandrels. In some exampleembodiments, the mandrels may be inflatable, adjustable, or expandingmandrels, or may include inflatable, adjustable, or expanding portionstherein, in order to form the surface features on the internal skins 306of the negative space spars 305. For example, inflatable mandrels orinflatable portions of mandrels may expand in size upon injection offluid, e.g., gas or liquid, into the mandrel and may reduce in size uponremoval of the fluid. Adjustable mandrels or adjustable portions ofmandrels may include movable or actuatable portions to selectivelymodify a shape or surface of the mandrel. Expanding mandrels orexpanding portions of mandrels may expand or reduce in size upon achange in condition, e.g., change in temperature, such as the thermallyexpanding mandrels described herein.

In further example embodiments, as described herein with respect toFIGS. 1C-1E, the component 302 shown in FIGS. 3A and 3B may also beformed with various surface features formed on an external skin 304 ofthe component 302. The surface features may be formed by correspondingsurface features included in surfaces of a molding tool. The varioussurface features may include corrugations, ribs, striations,protrusions, bumps, indentations, dimples, or other surface features, orcombinations thereof. In example embodiments, surface features of anytype, number, or arrangement may be formed on the external skin 304 ofthe component 302.

The various surface features may be formed by corresponding surfacefeatures included in surfaces of corresponding molding tools. In someexample embodiments, the molding tools may be inflatable, adjustable, orexpanding molding tools, or may include inflatable, adjustable, orexpanding portions therein, in order to form the surface features on theexternal skins 304 of the components 302. For example, inflatablemolding tools or inflatable portions of molding tools may expand in sizeupon injection of fluid, e.g., gas or liquid, into the molding tools andmay reduce in size upon removal of the fluid. Adjustable molding toolsor adjustable portions of molding tools may include movable oractuatable portions to selectively modify a shape or surface of themolding tools. Expanding molding tools or expanding portions of moldingtools may expand or reduce in size upon a change in condition, e.g.,change in temperature.

In example embodiments, the various surface features included on theinternal skins 306 of the negative space spars 305 and/or the externalskin 304 of the component 302 may further increase surface area ofcontact between the one or more skins formed by resin coatings andportions of the foam material composition, thereby increasinginterlaminar shear strength between the one or more skins and portionsof the foam material composition to further contribute to the increasedstructural strength of the component 302. Moreover, with the inclusionof surface features on one or more skins of the component 302 thatincrease structural strength, wall thicknesses between two or more skinsof the component may be further reduced, thereby further reducingmaterial usage and weight of the component 302 while increasingstructural strength.

In still further example embodiments, as described herein with respectto FIGS. 1C-1E, the component 302 shown in FIGS. 3A and 3B may also beformed with one or more support materials included at least partiallywithin or attached or adhered to the foam material composition 303. Forexample, the support materials may include a beam, rod, spar, or otherstructural support. In example embodiments, the support materials may beinserted into a molding tool and be surrounded by and molded into thefoam material composition 303. In other example embodiments, the supportmaterials may be inserted into, attached to, or adhered to a cast ormolded component 302 after the foam material composition has expandedand cured to form the component 302. The support materials may be formedof various types of materials, such as metals, plastics, woods,ceramics, polymers, or any other materials, or combinations thereof. Inaddition, the support materials may have any desired shape. In exampleembodiments, the component 302 may include any type, shape, number, orarrangement of support materials.

In example embodiments, the various support materials included at leastpartially within or attached or adhered to the foam material compositionmay further contribute to the increased structural strength of thecomponent 302. Moreover, with the inclusion of support materials as partof the component 302 that increase structural strength, wall thicknessesof one or more portions of the component may be further reduced, therebyfurther reducing material usage and weight of the component 302 whileincreasing structural strength.

While the description with respect to FIGS. 3A and 3B describes variousaspects of cast or molded components 302 individually, the variousfeatures described herein may be combined in various combinations. Forexample, external skins 304 of components 302 and/or internal skins 306of negative space spars 305 may include combinations of various surfacefeatures, such as both ribs and corrugations. In addition, a firstportion of a component 302 may include skins 304, 306 with varioussurface features, and a second portion of a component 302 may includesupport materials. Various other combinations of the various featuresdescribed herein may also be included in cast or molded components 302.

FIG. 4 is a flow diagram illustrating an example component with negativespace spar(s) and resin coating formation process 400, according to animplementation.

The process 400 may begin by preparing a molding tool and/or one or moremandrels, as at 402. For example, one or more release agents may beapplied to the molding tool and/or the one or more mandrels such that acast or molded component may be removed from the molding tool and/or theone or more mandrels may be removed from the component upon completionof the process 400. Further, the molding tool and/or the one or moremandrels may be designed with various draft angles to facilitate removalof a cast or molded component from the molding tool and/or removal ofthe one or more mandrels from the component. Moreover, the molding tooland/or the one or more mandrels may include various surface features asdescribed herein, in order to create corresponding surface features onexterior and/or interior surfaces of the component, such ascorrugations, ribs, striations, protrusions, bumps, indentations,dimples, or other surface features, or combinations thereof.

The molding tool may be a single-part, two-part, or multi-part moldingtool, and the molding tool may be formed from various materials, such asaluminum, carbon, steel, Inconel, other metals, ceramics, polymers,composites, or combinations thereof. In addition, the one or moremandrels may be solid or rigid mandrels, or inflatable, adjustable, orexpanding mandrels, and the one or more mandrels may be formed fromvarious materials, such as aluminum, carbon, steel, Inconel, othermetals, ceramics, polymers, composites, plastics, silicone, rubber, orcombinations thereof.

The process 400 may continue by preparing a resin coating material, asat 404. For example, the resin coating material may be a urethane resinthat cures upon application of heat and/or substantially at roomtemperature. In addition, the resin coating material may be modifiedwith additives such as microspheres or microbeads to reduce the weightof the resin coating material. Further, the resin coating material maybe modified with pigments or coloring agents to form a component with adesired color.

The process 400 may then proceed by applying the resin coating materialto the molding tool and/or one or more mandrels, as at 406. For example,the resin coating material may be applied to surfaces of the moldingtool and/or the one or more mandrels in a thin layer, e.g., having athickness of approximately 15-20 thousandths of an inch. In otherexample embodiments, the resin coating material may be applied in layershaving different thicknesses, as desired, that may affect the resultantweight and/or strength of the component.

The process 400 may continue by inserting the one or more mandrels intothe molding tool, as at 408. For example, the one or more mandrels maybe placed in position within or relative to the molding tool, in orderto form the component with desired negative space spars at particularpositions and/or with a particular arrangement.

The process 400 may then proceed by preparing the foam materialcomposition, as at 410. For example, the foam material composition maybe an expanding foam material composition, as described herein. Inaddition, the foam material composition may be a two-part or multi-partcomposition of different materials that may begin to expand and cureupon mixing of the different materials. In some embodiments, the foammaterial composition may expand and cure within seconds, e.g., 10-59seconds, or minutes, e.g., 1-30 minutes. In other embodiments, the foammaterial composition may expand and cure over a shorter or longerduration of time. In example embodiments, the foam material compositionmay be cooled, e.g., down to about 15 degrees Fahrenheit, in order toslow the expansion and curing of the foam material composition andthereby increase the duration of time during which the foam materialcomposition may be prepared and handled. Further, the foam materialcomposition may be modified with the addition of water or otheradditives to affect the expansion ratio.

The process 400 may then continue by injecting the foam materialcomposition into the molding tool, as at 412. In addition, the foammaterial composition may by injected around the one or more mandrelsthat are inserted into or placed relative to the molding tool. Forexample, the foam material composition may be metered into the moldingtool such that a precisely measured or determined amount of foammaterial composition is injected into the molding tool. The amount offoam material composition to be injected or metered may be determinedbased at least in part on a volume of the cast or molded component and adesired overvolume pressure to be generated during expansion and curingof the foam material composition within the molding tool. In furtherexample embodiments, prior to injecting the foam material compositioninto the molding tool, one or more support materials as described hereinmay be inserted or placed into the molding tool.

The process 400 may then proceed by closing the molding tool, as at 414.The closed molding tool may substantially seal the foam materialcomposition within the molding tool and/or around the one or moremandrels. In some example embodiments, prior to closing the moldingtool, one or more support materials as described herein may be insertedor placed into the molding tool. Then, the process 400 may continue byallowing the foam material composition to expand and cure, as at 416.Within the closed molding tool, the foam material composition maygenerate a desired overvolume pressure. In some example embodiments, thefoam material composition may expand and generate at least approximately10% overvolume pressure within the molding tool. In alternativeembodiments, different percentages of overvolume pressure may begenerated within the molding tool, e.g., approximately 5%, approximately8%, approximately 12%, or approximately 15%, or within a range ofapproximately 5% to approximately 20% overvolume pressure.

The process 400 may then continue by applying heat to the closed moldingtool and/or the one or more mandrels to cure the resin coating material,as at 418. For example, heat may be applied by placing the molding tooland/or the one or more mandrels in a curing oven. Alternatively, heatmay be applied to the molding tool and/or one or more mandrels by othermethods, such as by direct application of heat to one or more portionsof the molding tool and/or one or more mandrels. Some example resincoating materials may have a cure time of approximately a few hours atapproximately 150 degrees Fahrenheit. In other example embodiments,other combinations of curing temperatures and curing times may be usedbased at least in part on properties of the resin coating material. Thecuring of the resin coating material may at least partially overlap withthe expansion and curing of the foam material composition, in order toincrease the interlaminar shear strength between the resin coatingmaterial and the foam material composition. In alternative embodiments,the resin coating materials may cure substantially at room temperature,e.g., without the application of heat. For example, the resin coatingmaterials may have a cure time of approximately a few hours or a fewdays substantially at room temperature.

After completion of the expansion and curing of the foam materialcomposition and completion of the curing of the resin coating material,the process 400 may continue by stopping the application of heat to theclosed molding tool and/or the one or more mandrels, as at 420, and byopening the molding tool, as at 422. Then, the process 400 may proceedby removing the component from the molding tool, as at 424, and byremoving the one or more mandrels from the component, as at 426. Forexample, the release agents and/or draft angles of the molding tool mayfacilitate removal of the component from the molding tool. Likewise, therelease agents and/or draft angles of the one or more mandrels mayfacilitate removal of the one or more mandrels from the component. Insome example embodiments, after removing the component from the moldingtool and/or after removing the one or more mandrels from the component,one or more support materials as described herein may be inserted,attached, or adhered to the component. The process 400 may then end, asat 428.

The cast or molded component may include an external skin formed by aresin coating on an exterior surface of the component, and may alsoinclude one or more internal skins formed by resin coatings on interiorsurfaces of one or more negative space spars formed by the one or moremandrels. As described herein, the one or more negative space spars mayreduce material usage and weight of the component, and interlaminarshear strength between the one or more skins formed by resin coatingsand portions of the foam material composition may contribute to theincreased structural strength of the component.

All or portions of the process 400 described herein may be performed byautomated or semi-automated machinery that is controlled and/orprogrammed to perform one or more steps of the process 400. For example,automated or semi-automated machinery or robotics may prepare themolding tool and/or the one or more mandrels for molding components,and/or may insert the one or more mandrels into the molding tool.Further, automated or semi-automated machinery or robotics may preparethe resin coating material, and/or may apply the resin coating materialto the molding tool and/or the one or more mandrels. In addition,automated or semi-automated machinery or robotics may prepare the foammaterial composition, and/or may inject or meter the foam materialcomposition into the molding tool. Further, automated or semi-automatedmachinery or robotics may close the molding tool to allow the foammaterial composition to expand and cure, may apply heat to the closedmolding tool and/or the one or more mandrels to cure the resin coatingmaterial, and/or may open the molding tool upon completion. Moreover,automated or semi-automated machinery or robotics may remove thecomponent from the molding tool, and/or may remove the one or moremandrels from the component.

FIG. 5A is a schematic, perspective view diagram of a thermallyexpanding mandrel 505, according to an implementation 500.

As shown in FIG. 5A, the thermally expanding mandrel 505 may be formedin any desired shape, e.g., a wing, beam, or other component of anaerial vehicle, or any other beam, spar, rod, tube, or other component,of any other type of vehicle, machine, structure, device, or system.

The thermally expanding mandrel 505 may be formed of a materialcomposition 507 that facilitates expansion of the mandrel 505 uponapplication of heat. For example, the material composition 507 of themandrel 505 may include thermally expanding particles and bindermaterial. In example embodiments, the thermally expanding particles mayinclude micronized rubber particles, e.g., +/−80 mesh micron rubberdust. In alternative embodiments, the mandrel 505 may be formed frommicronized rubber powder, silicone rubber microspheres, silicone rubberpowder, or other thermally expanding particles. In still furtherembodiments, the mandrel 505 may be formed from combinations ofdifferent types of thermally expanding particles. Some or all of thethermally expanding particles may be recycled, recyclable, and/orreusable materials, such as micronized rubber particles formed fromcrushed and ground rubber tires.

In example embodiments, the binder material may include gypsum plaster.In alternative embodiments, the mandrel 505 may be formed from othertypes of binder material, such as other water-soluble binder materials.In still further embodiments, the mandrel 505 may be formed fromcombinations of different types of binder materials. Some or all of thebinder materials may be recycled, recyclable, and/or reusable materials,such as gypsum plaster.

The thermally expanding particles may have a relatively high coefficientof thermal expansion (CTE). For example, the thermally expandingparticles may have a CTE that is higher than a CTE of materials of amolding tool at least partially inside of which the mandrel 505 is to beused and/or placed. As described herein, the molding tool may be formedfrom various materials, such as aluminum, carbon, steel, Inconel, othermetals, ceramics, polymers, composites, or combinations thereof. Thethermally expanding particles of the mandrel 505 and materials of themolding tool may be selected such that the CTE of the thermallyexpanding particles of the mandrel 505 is higher than the CTE of thematerials of the molding tool. In this manner, the mandrel 505 may, uponapplication of heat, expand at a faster rate than the molding tool, suchthat the mandrel 505 may apply pressure to component materials appliedthereto against surfaces of the molding tool. In some exampleembodiments, expansion of the thermally expanding particles of themandrel 505 may generate at least approximately 10% overvolume pressurewithin the molding tool. In alternative embodiments, differentpercentages of overvolume pressure may be generated within the moldingtool, e.g., approximately 5%, approximately 8%, approximately 12%, orapproximately 15%, or within a range of approximately 5% toapproximately 20% overvolume pressure.

The thermally expanding mandrel 505 may be formed using various methodsand processes. For example, the mandrel 505 may be formed using moldingprocesses by injecting or metering the material composition 507 into amold of any desired shape and curing or otherwise hardening the materialcomposition 507. In other example embodiments, the mandrel 505 may beformed using 3-D printing processes by printing, applying, or buildingup the material composition 507 into any desired shape. In furtherexample embodiments, the mandrel 505 may be formed using machiningprocesses by forming a blank of material from the material composition507 and cutting, turning, drilling, grinding, polishing, or otherwisemachining the material composition 507 into any desired shape. Moreover,the mandrel 505 may be formed using any of these processes, otherprocesses, or combinations of different processes.

In example embodiments, the cast or molded components described herein,such as a wing, beam, or other component of an aerial vehicle, may be atleast partially formed using a thermally expanding mandrel 505 to formone or more negative space spars. In other example embodiments, the castor molded components may be any other component, e.g., a beam, spar,rod, tube, or other component, of any other type of vehicle, machine,structure, device, or system. Although FIGS. 5A-5D depict an examplewing as the cast or molded component, the systems and methods describedherein are not limited to wings or other components of aerial vehicles.

The cast or molded component that may be at least partially formed usinga thermally expanding mandrel 505 may be formed from a foam materialcomposition, e.g., urethane or polyurethane foams, expanding foammaterial compositions, self-skinning foam material compositions, and/orone or more resin coatings, e.g., urethane resins, on surfaces of thecomponent as described herein. In example embodiments, the foam materialcomposition may be an expanding foam material that expands and curessubstantially at room temperature. For example, the foam materialcomposition may expand and cure without the application of heat to thefoam material composition.

In further example embodiments, the foam material composition may be aself-skinning foam material composition. For example, upon expansion ofthe foam material composition that results in a pressure increase atinterfaces between the foam material composition and one or moresurfaces of a molding tool and/or between the foam material compositionand one or more surfaces of one or more mandrels inserted into themolding tool, an external skin may be formed on an exterior surface ofthe component and/or one or more internal skins may be formed on one ormore interior surfaces of the component.

Example foam material compositions may include four-pound foams,two-pound foams, or other types of foams. For example, a four-pound foamindicates an expansion ratio of approximately four pounds per cubicfoot, a two-pound foam indicates an expansion ratio of approximately twopounds per cubic foot, etc. In some example embodiments, the foammaterial composition may be modified with the addition of water or otheradditives to affect the expansion ratio. For example, the addition ofapproximately five drops of water to approximately 160 grams oftwo-pound foam may increase the expansion ratio by approximately 30%.

In some example embodiments, self-skinning foams may form skins on theirexterior surface facing a molding tool, or interior surfaces facingmandrels, upon generation of at least approximately 10% overvolumepressure within a molding tool. In alternative embodiments, differentpercentages of overvolume pressure may be generated within the moldingtool, e.g., approximately 5%, approximately 8%, approximately 12%, orapproximately 15%, or within a range of approximately 5% toapproximately 20% overvolume pressure. As described herein, one or morenegative space spars formed by the one or more mandrels may reducematerial usage and weight of the component, and interlaminar shearstrength between the one or more skins and portions of the foam materialcomposition may contribute to the increased structural strength of thecomponent.

The one or more resin coatings on surfaces of the component that may beat least partially formed using a thermally expanding mandrel 505 may beformed from urethane resins. In some example embodiments, the urethaneresins may be modified with microspheres or other additives to reducethe weight of the urethane resins. For example, the microspheres may behollow glass, plastic, or polymer microspheres or microbeads. In furtherexample embodiments, the urethane resins may be modified with pigmentsor other coloring agents in order to form a component having a desiredcolor. In example embodiments, the resin coatings may cure substantiallyat room temperature. For example, the resin coatings may cure withoutthe application of heat to the resin coatings. In alternativeembodiments, the resin coatings may be cured with the application ofheat. For example, the resin coatings may cure at a faster rate uponapplication of heat as compared to the rate of curing substantially atroom temperature.

The one or more resin coatings may be applied to surfaces of a moldingtool and/or one or more mandrels, and the one or more resin coatings maybe cured, e.g., upon application of heat. For example, the molding tooland/or the one or more mandrels may be heated, e.g., placed in an oven,in order to cure the resin coatings. The curing of the resin coatingsmay at least partially overlap with the expansion and curing of the foammaterial composition. As a result, the resin coatings may form anexternal skin on an exterior surface of the component, and/or one ormore internal skins on interior surfaces of the component. As describedherein, one or more negative space spars formed by the one or moremandrels may reduce material usage and weight of the component, andinterlaminar shear strength between the one or more skins formed byresin coatings and portions of the foam material composition maycontribute to the increased structural strength of the component.

In further example embodiments, the molded component that may be atleast partially formed using a thermally expanding mandrel 505 may beformed from component materials that are applied to, laid onto, orwrapped around the thermally expanding mandrel 505. The componentmaterials may include carbon fiber strips, carbon fiber tape, carbonfiber sheets, Kevlar, fiberglass, composites, other materials such aspolymers, plastics, ceramics, or combinations thereof that are appliedto, laid onto, or wrapped around the thermally expanding mandrel 505,and the component materials may be cured upon application of heat andpressure. For example, the molding tool and/or the one or more mandrelsmay be heated, e.g., placed in an oven, in order to expand and cure thecomponent materials. The thermally expanding mandrel 505 may expand uponapplication of heat, thereby expanding and applying pressure to thecomponent materials within the molding tool, and may cure the expandedand compressed component materials due to the application of heat andpressure.

In example embodiments including various combinations of foam materialcompositions, resin coatings, and/or component materials, the curing ofthe component materials and/or resin coatings may at least partiallyoverlap with the expansion and curing of the foam material composition.As a result, the component materials and/or resin coatings may form anexternal skin on an exterior surface of the component, and/or one ormore internal skins on interior surfaces of the component. As describedherein, one or more negative space spars formed by the one or moremandrels may reduce material usage and weight of the component, andinterlaminar shear strength between the one or more skins formed bycomponent materials and/or resin coatings and portions of the foammaterial composition may contribute to the increased structural strengthof the component.

Although FIG. 5A shows only a single thermally expanding mandrel 505that may be used to form a component or a negative space spar within acomponent having any desired shape, any other number, combination, orarrangement of one or more mandrels 505 may be used to form any desirednumber, combination, or arrangement of components or negative spacespars within one or more components. In example embodiments, thenegative space spars may reduce material usage and weight of thecomponent.

FIG. 5B is a schematic, perspective view diagram of another thermallyexpanding mandrel 505, according to an implementation.

As shown in FIG. 5B, the thermally expanding mandrel 505 may also beformed with one more surface features 508, 510, as described herein withrespect to FIGS. 1C-1E, formed on one or more portions of the exteriorsurface of the mandrel 505. The various surface features may includecorrugations 510, ribs 508, striations, protrusions, bumps,indentations, dimples, or other surface features, or combinationsthereof. While FIG. 5B shows a particular number, combination, andarrangement of ribs 508 a, 508 b, 508 c, 508 d and corrugations 510 a,510 b, 510 c, 510 d, 510 e, surface features of any type, number, orarrangement may be formed on one or more portions of the exteriorsurface of the mandrel 505, to thereby form corresponding surfacefeatures on interior surfaces of components and/or negative space sparsof components.

The various surface features may be formed on one or more portions ofthe exterior surface of the mandrel 505 such that upon expansion of thethermally expanding mandrel 505, e.g., due to the application of heat,corresponding surface features of any desired size, shape, combination,and/or arrangement may be formed on interior surfaces of componentsand/or negative space spars of components.

In example embodiments, the various surface features included on one ormore portions of the exterior surface of the mandrel 505 that formcorresponding surface features on interior surfaces of components and/ornegative space spars of components may further increase surface area ofcontact between one or more skins formed by self-skinning foam materialcompositions and/or resin coatings and portions of the foam materialcomposition, thereby increasing interlaminar shear strength between theone or more skins and portions of the foam material composition tofurther contribute to the increased structural strength of thecomponent. Moreover, with the inclusion of surface features on one ormore skins of the component that increase structural strength, wallthicknesses between two or more skins of the component may be furtherreduced, thereby further reducing material usage and weight of thecomponent while increasing structural strength.

In still further example embodiments, as described herein with respectto FIGS. 1C-1E, components that may be at least partially formed using athermally expanding mandrel 505 may also include one or more supportmaterials included at least partially within or attached or adhered tothe foam material composition, the resin coatings, and/or the componentmaterials. For example, the support materials may include a beam, rod,spar, or other structural support. In example embodiments, the supportmaterials may be inserted into a molding tool and be surrounded by andmolded into the foam material composition and/or the componentmaterials. In other example embodiments, the support materials may beinserted into, attached to, or adhered to a cast or molded componentafter the foam material composition, the resin coatings, and/or thecomponent materials have expanded and cured to form the component. Thesupport materials may be formed of various types of materials, such asmetals, plastics, woods, ceramics, polymers, or any other materials, orcombinations thereof. In addition, the support materials may have anydesired shape. In example embodiments, the component may include anytype, shape, number, or arrangement of support materials.

In example embodiments, the various support materials included at leastpartially within or attached or adhered to the foam materialcomposition, the resin coatings, and/or the component materials mayfurther contribute to the increased structural strength of thecomponent. Moreover, with the inclusion of support materials as part ofthe component that increase structural strength, wall thicknesses of oneor more portions of the component may be further reduced, therebyfurther reducing material usage and weight of the component whileincreasing structural strength.

While the description with respect to FIGS. 5A and 5B describes variousaspects of the thermally expanding mandrel 505 individually, the variousfeatures described herein may be combined in various combinations. Forexample, a first portion of the exterior surface of the mandrel 505 mayinclude corrugations 510, and a second portion of the exterior surfaceof the mandrel 505 may include ribs 508. In addition, a first portion ofthe exterior surface of the mandrel 505 may include ribs 508,corrugations 510, and/or other surface features, and a second portion ofthe exterior surface of the mandrel 505 may not include any surfacefeatures. Various other combinations of the various features describedherein may also be included in the thermally expanding mandrel 505.

FIG. 5C is a schematic, cross-sectional view diagram of a thermallyexpanding mandrel 505 within a molding tool 530 at a first temperature,according to an implementation.

As shown in FIG. 5C, a thermally expanding mandrel 505 may be placedwithin a molding tool 530 a, 530 b. In example embodiments, thethermally expanding mandrel 505 may include component materials 520applied or laid onto the exterior surface of the mandrel 505. Asdescribed herein, one or more portions of the exterior surface of themandrel 505 may include various surface features. Further, one or moreportions of the molding tool 530 a, 530 b may include various surfacefeatures, such as surface features that correspond to those included onthe exterior surface of the mandrel 505 or other surface features, asdesired.

The thermally expanding mandrel 505 may be formed from a thermallyexpanding material composition, e.g., micronized rubber particles andgypsum plaster. As shown in FIG. 5C, heat may not yet have been appliedto the mandrel 505 and/or the molding tool 530 a, 530 b. For example,the mandrel 505 and/or the molding tool 530 a, 530 b may be at a firsttemperature, e.g., room temperature or some other ambient temperature,at which the mandrel 505 has not expanded or has only minimallyexpanded.

FIG. 5D is a schematic, cross-sectional view diagram of a thermallyexpanding mandrel 505 within a molding tool 530 at a second temperature,according to an implementation.

As shown in FIG. 5D, heat may have been applied to the mandrel 505and/or the molding tool 530 a, 530 b. For example, the mandrel 505and/or the molding tool 530 a, 530 b may be at a second temperature,e.g., 150 degrees Fahrenheit, 250 degrees Fahrenheit, 300 degreesFahrenheit, or any other elevated temperature, at which the mandrel 505has expanded.

Due at least partially to the difference in CTE between the thermallyexpanding material composition of the mandrel 505 and the materials ofthe molding tool 530 a, 530 b, the mandrel 505 may expand at a fasterrate than the molding tool 530 a, 530 b. The expansion of the mandrel505 may cause expansion of the component materials 520 applied or laidonto the mandrel 505. In addition, the expansion of the mandrel 505 maycause application of pressure to the component materials 520 between theexterior surface of the mandrel 505 and interior surfaces of the moldingtool 530 a, 530 b. Further, the application of heat and pressure to thecomponent materials 520, e.g., by the mandrel 505 and/or the moldingtool 530 a, 530 b, may cause curing of the component materials 520 intoa component having a desired shape. Further, various surface featuresincluded on the exterior surface of the mandrel 505 and/or on theinterior surfaces of the molding tool 530 a, 530 b may cause theformation of corresponding surface features on interior and/or exteriorsurfaces, respectively, of the component materials 520.

As described further herein, after completion of the formation of thecomponent using the thermally expanding mandrel 505, the temperatures ofthe mandrel 505, molding tool 530 a, 530 b, and/or the component may bereduced to the first temperature, or some other handling temperature.Then, the component may be removed from the molding tool 530 a, 530 b,and the thermally expanding material composition of the mandrel 505 maybe washed out of the component, e.g., using hot, pressurized water.

In example embodiments in which the mandrel 505 is formed of micronizedrubber particles and gypsum plaster, the expansion of the mandrel 505due to application of heat may initiate at least partial breakage orfracturing of the micronized rubber particles from each other. Inaddition, the cooling of the mandrel 505 back to the first temperature,or some other handling temperature, may further cause breakage orfracturing of the micronized rubber particles from each other, at leastpartially due to their reduction in size as a result of cooling.Further, the application of hot, pressurized water may dissolve thegypsum plaster and cause additional, e.g., complete or nearly complete,breakage or fracturing of the micronized rubber particles from eachother. In this manner, the micronized rubber particles and gypsumplaster may be washed out of the component using water. Moreover, themicronized rubber particles may be recycled, e.g., using a centrifuge orother filtering processes, and reused to form other thermally expandingmandrels. Furthermore, the gypsum plaster may also be recycled, e.g.,using a plaster trap or other filtering processes, and also reused toform other thermally expanding mandrels.

FIG. 6 is a flow diagram illustrating an example component formationprocess using a thermally expanding mandrel 600, according to animplementation.

The process 600 may begin by preparing a molding tool, as at 602. Forexample, one or more release agents may be applied to the molding toolsuch that a cast or molded component may be removed from the moldingtool upon completion of the process 600. Further, the molding tool maybe designed with various draft angles to facilitate removal of a cast ormolded component from the molding tool. Moreover, the molding tool mayinclude various surface features as described herein, in order to createcorresponding surface features on exterior surfaces of the component,such as corrugations, ribs, striations, protrusions, bumps,indentations, dimples, or other surface features, or combinationsthereof.

The molding tool may be a single-part, two-part, or multi-part moldingtool, and the molding tool may be formed from various materials, such asaluminum, carbon, steel, Inconel, other metals, ceramics, polymers,composites, or combinations thereof.

The process 600 may continue by preparing a material composition for athermally expanding mandrel, as at 604. The material composition may bea thermally expanding material composition including thermally expandingparticles and binder material. As described herein, the thermallyexpanding particles may include micronized rubber particles or powder,silicone rubber microspheres, particles, or powder, or other thermallyexpanding particles having a CTE that is higher than a CTE of materialsof the molding tool. In addition, the binder material may be awater-soluble binder material, such as gypsum plaster. The relativeproportions of thermally expanding particles and binder material may bedetermined based at least in part on desired CTE of the mandrel,processes to be used to form the mandrel, physical properties of themandrel at various temperatures, physical properties of the molding toolat various temperatures, geometry of the component to be formed usingthe mandrel, and/or other factors related to the mandrel, mandrelformation, and/or component formation processes. The thermally expandingmaterial composition may expand upon application of heat, contract uponremoval of heat, break apart or fracture at least partially during orafter use, and/or be removable or dissolvable using hot, pressurizedwater.

The process 600 may then proceed by forming the mandrel using thematerial composition, as at 606. The mandrel may be formed in anydesired shape using various processes and methods. For example, themandrel may be formed by molding or casting the material composition ina molding tool, 3-D printing, machining, other processes, orcombinations thereof.

In further example embodiments, one or more release agents may beapplied to the mandrel such that the material composition may be removedfrom the component upon completion of the process 600. Further, themandrel may be designed with various draft angles to facilitate removalof one or more portions of the mandrel from the component. Moreover, themandrel may include various surface features as described herein, inorder to create corresponding surface features on interior surfaces ofthe component, such as corrugations, ribs, striations, protrusions,bumps, indentations, dimples, or other surface features, or combinationsthereof.

The process 600 may then continue to apply component material onto themandrel and/or the molding tool, as at 608. As described herein, thecomponent material may include carbon fiber strips, tape, sheets, orother layers, other types of materials, or combinations thereof, thatmay be applied to, laid onto, or wrapped around the mandrel and expandedand cured upon application of heat and pressure within the molding tool.In example embodiments, the component material may be applied in one ormore layers having various thicknesses, as desired, that may affect theresultant weight and/or strength of the component.

The process 600 may continue by inserting the mandrel into the moldingtool, as at 610. For example, the thermally expanding mandrel may beplaced in position within or relative to the molding tool, in order toform the component and/or a negative space spar within the component ata particular position and/or with a particular arrangement.

The process 600 may then proceed by closing the molding tool, as at 612.The closed molding tool may substantially seal the component materialwithin the molding tool and/or around the mandrel. Then, the process 600may continue by applying heat to the closed molding tool and/or themandrel to thermally expand the mandrel and expand, compress, and curethe component material, as at 614. For example, heat may be applied byplacing the molding tool and/or the mandrel in a curing oven.Alternatively, heat may be applied to the molding tool and/or themandrel by other methods, such as by direct application of heat to oneor more portions of the molding tool and/or the mandrel. Uponapplication of heat, the mandrel formed of a thermally expandingmaterial composition having a higher CTE than a CTE of the materials ofthe molding tool may expand at a faster rate than the molding tool. Theexpansion of the mandrel may correspondingly cause expansion of thecomponent material applied or laid onto the mandrel. In addition, themandrel may apply pressure to the component material against interiorsurfaces of the molding tool, thereby compressing and curing, e.g., byapplication of heat and pressure, the component material into thecomponent. In example embodiments, various combinations of curingtemperatures, curing pressures, and/or curing times may be determinedand used based at least in part on properties of the component material.

After completion of the expansion, compression, and curing of thecomponent material, the process 600 may continue by stopping theapplication of heat to the closed molding tool and/or the mandrel, as at616, and by opening the molding tool, as at 618. Then, the process 600may proceed by removing the component from the molding tool, as at 620,and by washing out the mandrel, or the thermally expanding materialcomposition of the mandrel, from the component, as at 622. For example,the thermally expanding material composition may be water-soluble suchthat the expanding material composition may be washed out of thecomponent using hot or warm, pressurized water.

As described herein, in example embodiments, the expansion of themandrel due to application of heat may initiate at least partialbreakage or fracturing of the thermally expanding particles from eachother. In addition, the cooling of the mandrel may further causebreakage or fracturing of the thermally expanding particles from eachother, at least partially due to their reduction in size as a result ofcooling. Further, the application of hot, pressurized water may dissolvethe binder material and cause additional, e.g., complete or nearlycomplete, breakage or fracturing of the thermally expanding particlesfrom each other. In this manner, the thermally expanding particles andwater-soluble binder material may be washed out of the component usingwater.

Then, the process 600 may continue by recycling the material compositionfor the mandrel, as at 624. For example, the thermally expandingparticles may be recycled, e.g., using a centrifuge or other filteringprocesses, and reused to form other thermally expanding mandrels.Furthermore, the binder material may also be recycled, e.g., using aplaster trap or other filtering processes, and also reused to form otherthermally expanding mandrels. The process 600 may then end, as at 626.

In example embodiments in which the component formed by the process 600also includes one or more foam material compositions, one or more resincoatings, and/or one or more support materials, as described herein, theprocess 600 may also include one or more of the steps described withrespect to processes 200, 400, such as preparation of the foam materialcomposition, injection of the foam material composition, preparation ofthe resin coating material, application of the resin coating material,insertion of one or more support materials, expansion and curing of thefoam material composition, and/or curing of the resin coating material,as described herein.

The component formed using a thermally expanding mandrel by the process600 described herein may include any desired shape, form, or geometry.Because the expanding material composition of the thermally expandingmandrel may be broken down, dissolved, and washed out of the component,a conventional mandrel having a fixed shape need not be removed from theinterior of the component after completion of the process. Furthermore,the component may be formed with various surface features on interiorsurfaces and/or exterior surfaces based at least in part oncorresponding surface features included on the thermally expandingmandrel and/or the molding tool. Moreover, while the example embodimentshave been described herein in the context of a single, thermallyexpanding mandrel used to form a component, multiple thermally expandingmandrels of any desired shapes, forms, or geometries may be usedtogether to form components with complex shapes, forms, and geometriesincluding one or more negative space spars in any combination orarrangement. Further, any of the various features described herein withrespect to any of the figures and example embodiments may be combined invarious combinations.

All or portions of the process 600 described herein may be performed byautomated or semi-automated machinery that is controlled and/orprogrammed to perform one or more steps of the process 600. For example,automated or semi-automated machinery or robotics may prepare themolding tool. Further, automated or semi-automated machinery or roboticsmay prepare the material composition for the thermally expandingmandrel, may form the mandrel using the material composition, and/or mayapply component material to the mandrel and/or the molding tool. Inaddition, automated or semi-automated machinery or robotics may insertthe thermally expanding mandrel into the molding tool, and/or may closethe molding tool. Further, automated or semi-automated machinery orrobotics may apply heat to the closed molding tool and/or the thermallyexpanding mandrel to expand the mandrel, and compress and cure thecomponent material, and/or may stop applying heat to the closed moldingtool and/or the thermally expanding mandrel. Moreover, automated orsemi-automated machinery or robotics may open the molding tool uponcompletion, and/or may remove the component from the molding tool.Furthermore, automated or semi-automated machinery or robotics may washout the thermally expanding mandrel from the component, and/or mayrecycle the thermally expanding material composition for the mandrel.

Each process described herein may be implemented by variousarchitectures described herein or by other architectures. The processesare illustrated as a collection of blocks in a logical flow. Some of theblocks represent operations that can be implemented in hardware,software, or a combination thereof. In the context of software, theblocks represent computer-executable instructions stored on one or morecomputer readable media that, when executed by one or more processors,perform the recited operations. Generally, computer-executableinstructions include routines, programs, objects, components, datastructures, and the like that perform particular functions or implementparticular abstract data types.

The computer readable media may include non-transitory computer readablestorage media, which may include hard drives, floppy diskettes, opticaldisks, CD-ROMs, DVDs, read-only memories (ROMs), random access memories(RAMs), EPROMs, EEPROMs, flash memory, magnetic or optical cards,solid-state memory devices, or other types of storage media suitable forstoring electronic instructions. In addition, in some implementations,the computer readable media may include a transitory computer readablesignal (in compressed or uncompressed form). Examples of computerreadable signals, whether modulated using a carrier or not, include, butare not limited to, signals that a computer system hosting or running acomputer program can be configured to access, including signalsdownloaded through the Internet or other networks. Finally, the order inwhich the operations are described is not intended to be construed as alimitation, and any number of the described operations can be combinedin any order and/or in parallel to implement the process. Additionally,one or more of the operations may be considered optional and/or notutilized with other operations.

Those skilled in the art will appreciate that, in some implementations,the functionality provided by the processes and systems discussed abovemay be provided in alternative ways, such as being split among moresoftware modules or routines or consolidated into fewer modules orroutines. Similarly, in some implementations, illustrated processes andsystems may provide more or less functionality than is described, suchas when other illustrated processes instead lack or include suchfunctionality respectively, or when the amount of functionality that isprovided is altered. In addition, while various operations may beillustrated as being performed in a particular manner (e.g., in serialor in parallel) and/or in a particular order, those skilled in the artwill appreciate that, in other implementations, the operations may beperformed in other orders and in other manners.

The various processes and systems as illustrated in the figures anddescribed herein represent example implementations. The processes andsystems may be implemented in software, hardware, or a combinationthereof in other implementations. Similarly, the order of any processmay be changed, and various elements may be added, reordered, combined,omitted, modified, etc., in other implementations.

From the foregoing, it will be appreciated that, although specificimplementations have been described herein for purposes of illustration,various modifications may be made without deviating from the spirit andscope of the appended claims and the features recited therein. Inaddition, while certain aspects are presented below in certain claimforms, the inventors contemplate the various aspects in any availableclaim form. For example, while only some aspects may currently berecited as being embodied in a computer readable storage medium, otheraspects may likewise be so embodied. Various modifications and changesmay be made as would be obvious to a person skilled in the art havingthe benefit of this disclosure. It is intended to embrace all suchmodifications and changes and, accordingly, the above description is tobe regarded in an illustrative rather than a restrictive sense.

What is claimed is:
 1. A method of manufacturing a component,comprising: applying a urethane resin material composition to a mandreland a molding tool; inserting the mandrel into the molding tool;metering a foam material composition into the molding tool; closing themolding tool for a period of time, wherein the foam material compositionexpands and cures to form a component having a negative space sparduring the period of time; applying heat to the molding tool during atleast a portion of the period of time, wherein the urethane resinmaterial composition cures to form a skin of the component during the atleast a portion of the period of time; opening the molding tool afterthe period of time; removing the component from the molding tool; andremoving the mandrel from the negative space spar of the component. 2.The method of claim 1, wherein the urethane resin material compositionapplied to the molding tool forms an external skin on an exteriorsurface of the component during the at least a portion of the period oftime.
 3. The method of claim 1, wherein the urethane resin materialcomposition applied to the mandrel forms an internal skin on an interiorsurface of the negative space spar of the component during the at leasta portion of the period of time.
 4. The method of claim 1, wherein theurethane resin material composition comprises at least one ofmicrospheres or pigment.
 5. A method, comprising: applying a resinmaterial composition to a mandrel and a molding tool; inserting themandrel into the molding tool; injecting a foam material compositioninto the molding tool; closing the molding tool for a period of time,wherein the foam material composition expands and cures to form acomponent having a negative space spar during the period of time, andwherein the resin material composition cures to form a skin of thecomponent during at least a portion of the period of time.
 6. The methodof claim 5, further comprising: opening the molding tool after theperiod of time; removing the component from the molding tool; andremoving the mandrel from the negative space spar of the component. 7.The method of claim 5, wherein the resin material composition forms theskin on an interior surface of the negative space spar and an exteriorsurface of the component during the at least a portion of the period oftime.
 8. The method of claim 7, wherein the mandrel includes at leastone surface feature that forms a corresponding internal surface featureon the skin of the interior surface of the negative space spar of thecomponent.
 9. The method of claim 8, wherein the at least one surfacefeature of the mandrel includes at least one corrugation extending alonga long axis of the mandrel.
 10. The method of claim 8, wherein the atleast one surface feature of the mandrel includes at least one of a rib,protrusion, bump, indentation, or dimple.
 11. The method of claim 7,wherein the resin material composition is applied to the molding tool,and the molding tool includes at least one surface feature that forms acorresponding external surface feature on the skin of the exteriorsurface of the component.
 12. The method of claim 5, wherein the mandrelis at least one of an inflatable mandrel, adjustable mandrel, orexpanding mandrel.
 13. The method of claim 5, further comprising:inserting a support material into the molding tool prior to at least oneof injecting the foam material composition into the molding tool orclosing the molding tool for the period of time.
 14. The method of claim13, wherein the support material includes at least one of a beam, rod,or spar.
 15. The method of claim 5, wherein inserting the mandrel intothe molding tool comprises inserting a plurality of mandrels into themolding tool, and wherein the component includes a respective pluralityof negative space spars.
 16. A method of manufacturing a component,comprising: applying a first resin material composition to a firstsurface of a molding tool; applying a second resin material compositionto a second surface of a mandrel; inserting the mandrel into the moldingtool; metering a foam material composition into the molding tool;closing the molding tool for a period of time such that: the foammaterial composition expands and cures, during the period of time, toform a component having a negative space spar formed by the mandrel; thefirst resin material composition in contact with the first surface ofthe molding tool cures to form an external skin of the component; andthe second resin material composition in contact with the second surfaceof the mandrel cures to form an interior skin of the component; andremoving the mandrel from the negative space spar of the component. 17.The method of claim 16, wherein the first surface of the molding toolincludes at least one surface feature that forms a correspondingexternal surface feature on the exterior skin of the component.
 18. Themethod of claim 16, wherein the second surface of the mandrel includesat least one surface feature that forms a corresponding internal surfacefeature on the interior skin of the negative space spar of thecomponent.
 19. The method of claim 16, wherein: applying the secondresin material composition to the second surface of the mandrelcomprises applying the second resin material composition to a pluralityof mandrels; and inserting the mandrel into the molding tool comprisesinserting the plurality of mandrels into the molding tool, and whereinthe component includes a respective plurality of negative space spars.20. The method of claim 16, wherein the first resin material compositionand the second resin material composition comprise at least one ofmicrospheres, microbeads, or a pigment.